Semiconductor manufacturing processes are highly sensitive to contamination because depositing even a tiny particle or other contaminants (metals, not volatile residue) on a semiconductor wafer can lead to defects. Therefore, it is common to employ ultraclean purifiers having membranes that remove submicron particles, residues like metal ions and other contaminants. Although different filtration modules have been developed to filter semiconductor manufacturing liquids, rectangular shaped filters have been avoided because rectangular designs are typically unable to meet the filtering and flow rate requirements in a compact design that can withstand the pressures used in semiconductor manufacturing. Therefore, many existing filter modules are cylindrical, having a housing with a one-piece cylindrical bowl or sleeve in which the filter membrane resides. Typically, these filters contain a circular pleated filter membrane that is encased between an external cage and an internal core. Fluid enters the filter module from the top or bottom, flowing between the sleeve before passing through the cage, passing through the filter membrane to the hollow core and exiting the module.
Existing cylindrical filter modules suffer several shortcomings. One deficiency is that the circular pleated membrane unduly restricts fluid flow because the membrane must be more tightly packed towards the center in order to achieve the circular configuration. Another deficiency is that the cylindrical housings are molded or extruded as single pieces, making it difficult or impossible to add geometries that run perpendicular to the cylinder's axis. Furthermore, many existing filter modules are difficult to install and replace. Since many liquids used in semiconductor manufacturing are corrosive or toxic, filter module replacement presents a danger to workers.
Current filtration systems that employ cylindrical filters have limited configurability. In many cases, filters are connected through multiple units in a fixed configuration, making it difficult to change the flow through the filters from serial to parallel as needed. Additionally, many filtration systems use only a single type of filter, limiting the ability to apply different filters for different purposes or particle sizes in a single filtration system.